This invention relates to a solar cell module, and in particular to a thin film solar cell module which is useful for a power generation from sunlight.
There is known the following method as one of the methods for manufacturing a thin film solar cell module. Namely, a transparent electrode layer, a photoelectric semiconductor layer and a metal layer, which have been deposited on a light-transmitting glass substrate, are at least partially worked by means of an optical beam thereby to partition these layers into a plurality of cells to isolate one cell from another cell, which are then electrically connected with each other, and after terminals are attached to these cells, the reverse surface (the surface opposite to the light-transmitting glass substrate) is sealed with an encapsulant such as a resin for protecting the power-generating portions thereof, the resultant body being finally fixed to a mounting frame.
The dielectric strength is one of the characteristics demanded for a solar cell module manufactured in this manner. The dielectric strength of solar cell module can be determined generally by measuring the withstand voltage between a terminal of solar cell and the frame.
The thin film solar cell is generally constituted by a lamination of thin films such as a transparent electrode layer, a photoelectric semiconductor layer and a metal layer, and most of these layers are generally formed through a vapor phase reaction. Accordingly, it is generally difficult, in the process of forming such a laminate through this vapor phase reaction, to restrict film forming area to so-called active portion of the solar cell. Occasionally, any of these layers may extend also to the other surface of the substrate. If such a substrate is attached as it is to the frame, it is more likely that the electric potential of the frame may become identical with that of the active portion of the solar cell. Because of this, the conventional thin film solar cells are generally poor in dielectric strength.
With a view to overcome this problem, there has been proposed a method wherein the active region occupying the central portion of solar cell is electrically isolated from the peripheral region of solar cell, which has much possibilities of being electrically contacted with the frame, by making use of a laser beam which is employed in the patterning of the layers at the occasion of electrical connection of cells. However, the solar cell module manufactured by making use of this method is accompanied with a problem that even though the solar cell exhibits an excellent dielectric strength immediately after the manufacture thereof, this property of dielectric strength is sharply deteriorated when the solar cell module is left in an environment of high temperature and high humidity. Accordingly, this method has been found poor not only in manufacturing yield due to a low reliability but also in productivity, thus making this method useless in industrial viewpoint.
The thin film solar cell module of this kind is especially accompanied with a problem that when it is employed out of door, water may be penetrated into the active portion (power generating region) of the solar cell, thus denaturing or corroding this active portion, resulting in a deterioration of the power-generating property thereof. One of the causes of this problem is the penetration of water through an interface between the substrate and the encapsulant at the peripheral portion of the solar cell module. Therefore, it is highly desired to prevent the penetration of water through a peripheral portion of the solar cell module and to improve the weather resistance of the solar cell module.
Therefore, the object of the present invention is to provide a solar cell module, which makes it possible, while assuring a high productivity, to ensure the insulation between the power-generating active portion thereof and the peripheral region thereof, or the insulation between the solar cell module and the frame thereof.
Another object of the present invention is to provide a solar cell module, which is excellent in dielectric strength, free from deterioration of property due to a corrosion after sealing thereof and capable of maintaining a sufficient strength of glass substrate, and which can be manufactured in a stable manufacturing process and in high productivity.
Still another object of the present invention is to provide a solar cell module, which is capable of preventing the penetration of water once it is sealed with an encapsulant thereby making it possible to prevent the power-generating property thereof from being deteriorated due to a corrosion by water, and which can be manufactured with high productivity.
According to this invention, there is provided a thin film solar cell module which comprises a first electrode layer, a semiconductor layer and a second electrode layer, which are deposited on a substrate and at least part of which is worked to partition these layers into a plurality of cells which are electrically connected with each other and sealed with an encapsulant; wherein at least part of at least one of the first electrode layer, the semiconductor layer and the second electrode layer, which is located at the periphery of the substrate, is removed by mechanical means or by means of laser beam.
According to this invention, there is also provided a solar cell module which comprises a laminate layer comprising a first electrode layer, a semiconductor layer and a second electrode layer, which are deposited on a substrate and patterned thereby to partition these layers into a plurality of solar cells which are electrically connected with each other and sealed with an encapsulant; wherein a periphery of the electrically connected solar cells is surrounded by a high adhesive strength region, and adhesive strength between the high adhesive strength region and the encapsulant is larger than the adhesive strength between the encapsulant and the electrically connected solar cells.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.